MUSYCA: a quasi synchronous CDMA VLSI processor and its application to multiple access

Quasi synchronous CDMA (QS-CDMA) is a quite well known technique which offers both the flexibility of a CDMA (access and resource management techniques) and the capacity of a TDMA system. QS-CDMA is advantageous if the propagation channel is near from line of sight and if the coherence time is high. Hence QS-CDMA has formerly been proposed for GEO satellite and cable modem uplink communication. An implementation of a QS-CDMA digital processor is proposed along with a test platform and performances evaluation. This PHY layer chip is able to handle a large number of simultaneous users, proposes an original connection mechanism and also provides all control information for the MAC layer. It offers a great flexibility due to its high programmability. An application to the uplink of a cable modem is proposed.